The case of a woman accused of trying to poison her romantic rival is returning to the U.S. Supreme Court.

The court ruled in 2011 that Carol Anne Bond had standing to challenge Congress’ power to enact the chemical terrorism law used to prosecute her. The law was passed to comply with a treaty aimed at preventing the spread of chemical weapons.

Now the court will consider whether Congress has authority under its treaty power to pass a law that allegedly intrudes on state police powers, report the Washington Post, SCOTUSblog and Reuters.

The Philadelphia-based 3rd U.S. Circuit Court of Appeals had upheld the federal chemical weapons statute in May. The court said it was bound by a 1920 U.S. Supreme Court case, Missouri v. Holland, that said laws passed pursuant to treaties are not subject to 10th Amendment scrutiny.

Now the court has granted cert on two questions, SCOTUSblog says. The first is whether the Constitution limits Congress’ authority to implement a valid treaty. The second is whether the chemical weapons law used to prosecute Bond applies to “ordinary poisoning cases.”

The cert petition (PDF) questions the 3rd Circuit’s reading of Missouri v. Holland. “Whether or not that is the best reading of Holland or whether Holland needs to be reconsidered,” the cert petition says, “it is clear that only this court can correct this injustice and clarify that statutes enacted to implement valid treaties, like all other laws, must comply with the Constitution’s bedrock structural limits on our system of limited but enumerated federal powers.”

Bond was sentenced to six years in prison after pleading guilty while reserving her right to challenge the law. She was accused of trying to poison a onetime friend who became pregnant from an affair with Bond’s husband. Prosecutors said Bond spread chemicals on the woman’s mailbox, doorknob and car door. The intended target suffered a chemical burn to her thumb.

According to Reuters, the case “presents an unusual clash between the desire to enforce international treaty norms, including provisions designed to thwart terrorism, and the 10th Amendment to the U.S. Constitution, which limits federal power.” The case is Bond v. United States.